Presenter: Charles W. Melnyk

Affiliation: Swedish University of Agricultural Sciences, Uppsala, Sweden

Email: charles.melnyk@slu.se

Abstract: For millennia, people have used grafting to improve and propagate plants. Grafting is widely used in horticulture to increase stress tolerance, improve disease resistance and promote yields. However, we have a limited understanding of how two plants successfully fuse tissues and form vascular connections. Here, I will present my group’s latest efforts to understand the molecular basis for how plants successfully graft. I will discuss our work using Arabidopsis thaliana grafting to understand the physiology, genes and pathways involved in successful graft formation. I will also show our recent work on the role of sugars and the importance of sugar accumulation and depletion around the graft junction. Finally, incompatibility is a major cause of graft failure, and I will present our work on understanding and overcoming this phenomenon in monocots and conifers. Altogether, our research sheds light on the mechanism of graft formation in diverse species and provides clues for improving grafting success rates.

Keywords: plant grafting; regeneration; graft incompatibility; sugars; Arabidopsis

Presenter: Michitaka Notaguchi

Affiliation: Kyoto University, Japan; Bioscience & Biotechnology Center, Nagoya University, Japan; Key Laboratory of Horticultural Plant Biology, Huazhong Agricultural University, China

Email: notaguchi.michitaka.4k@kyoto-u.ac.jp

Abstract: Grafting is a technique that joins two different plants together to grow as one. For fruit trees, it is used for dwarfing and clonal propagation; for vegetables, it aims to impart disease resistance and enhance yield. While grafting was traditionally limited to closely related species, plants capable of grafting have been discovered even among distantly related plants from different families, such as those in the tobacco genus Nicotiana. This opens new avenues for breeding techniques combining grafting with biotechnology, like flowering promotion using florigen. This seminar will introduce the molecular mechanisms of cell wall adhesion and xylem formation, as well as cell proliferation mediated by autophagy, revealed through the analysis of interfamily grafting in Nicotiana plants. We will also discuss future prospects for the technological application of these findings.

Keywords: Grafting; cell–cell adhesion; autophagy; cell division; vascular formation

Presenter: Yunyun Cao, Henming Wu, Alice Y. Cheung*, Qiaohong Duan*

Affiliation: Shandong Agricultural University, China; University of Massachusetts Amherst, USA

Email: duanqh@sdau.edu.cn; acheung@biochem.umass.edu

Abstract: Flowering plants have evolved numerous interspecific prezygotic reproductive barriers to prevent production of unfavourable offspring. We showed earlier that the SI female determinant, S-locus receptor kinase (SRK), also recognizes interspecific pollen. The recognition then triggers high levels of reactive oxygen species (ROS) in the stigma of heading Chinese cabbage (Brassica rapa L. ssp. pekinensis), leading to the rejection of interspecific pollen. ROS are regulated by FERONIA receptor kinase and produced by NADPH oxidases. Here, we identified the pollen signal that binds to SRK and triggers these incompatible responses in the stigma. We also investigated the molecular mechanisms underlying interspecific incompatible responses. We also offer paths to achieve efficient distant breeding in Brassicaceae crops.

Keywords: FERONIA receptor kinase; S-locus receptor kinase (SRK); interspecific barrier; Brassicaceae; distant breeding

Presenter: J. Peter Etchells*

Affiliation: Department of Biosciences, Durham University, UK

Email: Peter.Etchells@durham.ac.uk

Abstract: Wood constitutes the largest reservoir of terrestrial biomass. Composed of xylem, it arises from one side of the vascular cambium, a bifacial stem cell niche that also produces phloem on the opposing side. Until recently it was unknown which molecular factors endow cambium stem cell identity. Here we show that TDIF ligand‑activated PXY receptors promote the expression of CAMBIUM‑EXPRESSED AINTEGUMENTA‑LIKE (CAIL) transcription factors to define cambium stem cell identity in the Arabidopsis root. By sequestrating the phloem‑originated TDIF, xylem‑expressed PXY confines the TDIF signaling front, resulting in the activation of CAIL expression and stem cell identity in only a narrow domain. These findings show how signals emanating from cells on opposing sides ensure robust yet dynamically adjustable positioning of a stem cell layer.

Keywords: Stem cells; cambium; vascular tissues; secondary growth; wood formation

Presenter: Jingze Zang, Patrick Duckney, Verena Kriechbaumer, Patrick Hussey, Pengwei Wang*

Affiliation: Huazhong Agricultural University, China; Oxford Brookes University, UK; Durham University, UK

Email: wangpengwei@mail.hzau.edu.cn

Abstract: The cortical endoplasmic reticulum (ER) network is connected to the plasma membrane (PM) through the ER‑PM contact sites (EPCSs), whose architectural integrity is maintained by conserved scaffolding proteins. Emerging evidence in plants reveals a direct spatial coordination between EPCSs and cytoskeletal elements, where perturbation of ER‑PM tethering components induces cytoskeletal reorganization, thereby modulating multiple cellular processes including environmental signal sensing, polarized growth, and cytokinesis. Despite these functional connections, the mechanistic basis for ER–cytoskeleton coordination at EPCSs remains unclear. Our recent work elucidates a molecular bridge at this interface: the ER membrane‑anchored VAP27‑1 tether directly engages with actin nucleation machinery, including the SCAR/WAVE regulatory complex, to orchestrate actin cytoskeleton remodeling. Here, I will provide an overview of current understanding of ER–cytoskeleton interplay in plants, with particular emphasis on the structural determinants maintaining EPCS–cytoskeleton associations and their functional implications for plant development. By integrating recent advances in live‑cell imaging, proteomic analyses, and mutant phenotyping, we propose an updated model where EPCSs serve as signaling platforms that coordinate membrane trafficking with cytoskeletal reorganization.

Keywords: ER–PM contact sites (EPCSs); cytoskeleton remodeling; VAP27‑1; actin nucleation; membrane trafficking

Presenter: Jim Rowe*

Affiliation: School of Biosciences, University of Sheffield, UK

Email: james.rowe@sheffield.ac.uk

Abstract: The escalating frequency of ‘flash droughts’, rapid farmland desiccation due to soaring temperatures and arid climates, threatens global food security. Understanding plant stress responses is critical if we are to generate new crops that can both withstand stress but also continue to thrive and deliver optimal yields. Plant responses to drought and low humidity are controlled by the plant hormone, abscisic acid (ABA), which accumulates under stress, rebalancing plant hydraulics to reduce water loss. To understand how ABA regulates stress responses and achieve our vision of stress‑resilient crops, we must be able to determine in which cells ABA is made and how ABA levels change during stress. Despite nearly 60 years of research, these key questions remained difficult to answer, until recently. I developed genetically encoded tools allowing us to see and quantify ABA concentrations in living plants. This major innovation resulted in surprising and illuminating results. We found that different types of stress elicited different patterns of ABA accumulation. Now, we are investigating the functional relevance of each of these context‑dependent, spatially defined hormone accumulations—to understand how ABA functions in stomatal and non‑stomatal responses, to allow plants to survive stress.

Keywords: Abscisic acid (ABA); drought stress; plant hormone signaling; stress resilience; genetically encoded biosensors

Presenter: Chaonan Zhang, Zhenhui Guo, Hansu Zhao, Alexis De Angeli*, Jingbo Zhang*

Affiliation: China Agricultural University, China; IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, France

Email: jingbozhang@cau.edu.cn

Abstract: The vacuole, a multifunctional and complex compartment, takes up most of the cellular space in mature plants and around 90% of the intracellular metabolites are stored in the vacuole to regulate osmoregulation and turgor pressure, stomatal movements, metal tolerance, nitrate absorption in plants. To keep intracellular anion homeostasis and fine‑tune cytosolic concentration, anion transporters and channels are required across the vacuolar membrane. In our research, we identified and characterized vacuolar anion channels of ZmVPEs, ZmCLCs and ZmMATEs in maize to maintain intracellular phosphate, nitrate and chloride homeostasis in response to soil environmental stresses. Furthermore, their upstream regulatory mechanisms are also studied. The study of these vacuolar anion channels and their regulators will enable the breeding of crops for higher resilience, nutrient use efficiency and grain yield.

Keywords: vacuole; anion channels; abiotic stress; nutrient use efficiency; maize

Presenter: Jian Jonathan Michael Dragwidge, Matthieu Buridan, Julia Kraus, Thibault Kosuth, Clément Chambaud, Lysiane Brocard, Klaas Yperman, Evelien Mylle, Michaël Vandorpe, Dominique Eeckhout, Geert De Jaeger, Roman Pleskot, Amelie Bernard*, Daniël Van Damme*

Affiliation: Ghent University & VIB-PSB, Belgium; Univ. Bordeaux, France; Czech Academy of Sciences, Czech Republic

Email: Daniel.VanDamme@psb.vib-ugent.be

Abstract: Plants experience hyperosmotic stress due to drought and salinity. This causes cellular water loss, decreases turgor pressure, and reduces cell volume. Osmotic stress affects plasma membrane tension, a property which must be maintained to enable cell signalling and growth. How plants maintain plasma membrane tension as the cell volume shrinks during hyperosmotic stress remains unclear. Here, we identified an autophagy pathway which degrades plasma membrane‑derived clathrin‑coated vesicles (CCVs) during osmotic stress. Time‑lapse imaging following osmotic shock shows a reduction in cell volume that correlates with an acute induction of autophagy. Using correlative‑light and electron microscopy (CLEM) combined with electron tomography (ET), we visualised CCVs physically attached to autophagosome membranes. High‑resolution fluorescent microscopy showed that these CCVs are labelled with the endocytic TSET/TPLATE complex, which co‑localize with autophagosomes specifically upon osmotic stress. The TPLATE complex subunits, AtEH1/Pan1 and AtEH2/Pan1, contain conserved ATG8 interaction motifs, which we demonstrate to directly interact with ATG8. We therefore propose that AtEH/Pan1 proteins act as selective autophagy receptors for plasma membrane‑derived CCVs. We postulate that this pathway removes excess membrane during hyperosmotic stress to maintain plasma membrane tension and integrity. These findings contribute to our physiological understanding of how plants adapt to drought and salt stress.

Keywords: endocytosis; clathrin; osmotic stress; autophagy; endomembrane interconnectivity

Presenter: Facundo Romani*

Affiliation: Department of Plant Sciences, University of Cambridge, UK

Email: fr391@cam.ac.uk

Abstract: Land plants evolved an extraordinary diversity of epidermal cell types that mediate ecological interactions and determine important agronomic traits. Among them, secretory structures such as glandular trichomes, resin ducts, and oil glands have evolved repeatedly, highlighting the evolutionary plasticity of plant epidermis. The earliest known secretory structures are the intracellular oil bodies of liverworts. Oil bodies are organelles that synthesize and compartmentalize terpenoids and other specialized metabolites, providing a defense against herbivores. Marchantia polymorpha has recently emerged as a key model for evolutionary developmental biology at a macroevolutionary scale, offering genetic and genomic tools to investigate how novel cell types arise. Using this system, we have identified a network of transcription factors that orchestrate successive stages of oil body cell differentiation, revealing both conserved and lineage‑specific regulatory modules compared to vascular plants. These findings provide a molecular framework for understanding how secretory specialization evolved at the dawn of terrestrial plant life. Our work bridges comparative genomics, cell biology, and molecular genetics to trace the origins of secretory innovation in land plants, opening new perspectives for engineering plant development and function.

Keywords: secretory structures; liverworts; Marchantia; transcription factors; evo‑devo

Presenter: Moritz K. Nowack*

Affiliation: Ghent University & VIB-PSB, Belgium

Email: moritz.nowack@vib.be

Abstract: Although seemingly paradoxical, death is an inherent part of life. Genetically programmed death of individual cells (PCD) is key to the health and the development of multicellular eukaryotes. While PCD processes are intensely studied in the biomedical field due to their implications in inflammation, (auto)‑immunity, or cancer, PCD research in plants still is pioneering work. Although key animal PCD pathways are not conserved in plants, PCD is as crucial for the development and health of plants as it is for animals. Without PCD, plants would not be able to efficiently transport water, form seeds and fruit, or defend themselves against pathogens. Hence, plant PCD is not only appealing as a fundamental research frontier, but also provides a largely untapped application potential to improve yield stability and stress resilience of crops. We are focusing on developmentally controlled PCD (dPCD) as a means to understand how plants evolved and instrumentalized cell death as a fundamental mechanism of development. Using root cap turnover in Arabidopsis thaliana as a potent dPCD model system, we identified an extensive gene regulatory network coordinating cellular differentiation and PCD preparation. Downstream, we discovered a rapid succession of cellular decompartmentalization events that brings about the irreversible cessation of cellular vital functions to execute cell death and orchestrate post‑mortem corpse clearance. Equipped with this knowledge, we are now unravelling the players and their molecular control mechanisms that are responsible for cell death execution in plants.

Keywords: plant development; programmed cell death; root cap; cell biology

Presenter: Shuang Wu*

Affiliation: Department of Biosciences, Durham University, UK

Email: Peter.Etchells@durham.ac.uk

Abstract: Wood constitutes the largest reservoir of terrestrial biomass. Composed of xylem, it arises from one side of the vascular cambium, a bifacial stem cell niche that also produces phloem on the opposing side. Until recently it was unknown which molecular factors endow cambium stem cell identity. Here we show that TDIF ligand‑activated PXY receptors promote the expression of CAMBIUM‑EXPRESSED AINTEGUMENTA‑LIKE (CAIL) transcription factors to define cambium stem cell identity in the Arabidopsis root. By sequestrating the phloem‑originated TDIF, xylem‑expressed PXY confines the TDIF signaling front, resulting in the activation of CAIL expression and stem cell identity in only a narrow domain. These findings show how signals emanating from cells on opposing sides ensure robust yet dynamically adjustable positioning of a stem cell layer.

Keywords: stem cells; cambium; vascular tissues; secondary growth; wood formation

Presenter: Jim Rowe*

Affiliation: School of Biosciences, University of Sheffield, UK

Email: james.rowe@sheffield.ac.uk

Abstract: The escalating frequency of ‘flash droughts’, rapid farmland desiccation due to soaring temperatures and arid climates, threatens global food security. Understanding plant stress responses is critical if we are to generate new crops that can both withstand stress but also continue to thrive and deliver optimal yields. Plant responses to drought and low humidity are controlled by the plant hormone, abscisic acid (ABA), which accumulates under stress, rebalancing plant hydraulics to reduce water loss. To understand how ABA regulates stress responses and achieve our vision of stress‑resilient crops, we must be able to determine in which cells ABA is made and how ABA levels change during stress. Despite nearly 60 years of research, these key questions remained difficult to answer, until recently. I developed genetically encoded tools allowing us to see and quantify ABA concentrations in living plants. This major innovation resulted in surprising and illuminating results. We found that different types of stress elicited different patterns of ABA accumulation. Now, we are investigating the functional relevance of each of these context‑dependent, spatially defined hormone accumulations—to understand how ABA functions in stomatal and non‑stomatal responses, to allow plants to survive stress.

Keywords: Abscisic acid (ABA); drought stress; plant hormone signaling; stress resilience; genetically encoded biosensors

Presenter: Tim Kelliher*, Jian Lv, Dawei Liang, Rachel Egger

Affiliation: North Carolina State University, USA; Syngenta Crop Protection LLC, USA; Syngenta Biotechnology China Co. Ltd., China

Email: tjkellih@ncsu.edu

Abstract: Flowering plant sexual reproduction requires double fertilization, yielding embryo and endosperm seed compartments: the latter supports embryo growth and seed germination. My lab develops new breeding technologies to accelerate germplasm improvement and reduce the cost of goods in seed production. First, we used genome editing of the MATRILINEAL gene to create novel maternal haploid inducers and doubled haploid platforms in maize (Zea mays) and rice (Oryza sativa). Next, we edited essential centromeric histone (CENH3) genes in wheat (Triticum aestivum) to induce paternal haploids. Then, we co‑opted haploid induction to serve as a delivery tool for genome editing traits in diverse monocot and dicot species. “HI‑Edit” was demonstrated in corn, wheat, and Arabidopsis, and the overall efficiency has been improved by several hundred‑fold in corn through a series of technical innovations. Next, we combined a CENH3 paternal haploid inducer with sterile cytoplasm to enable “cyto‑swapping”, accelerating development of new maize hybrid varieties. Finally, we serendipitously discovered that emasculated sunflowers (Helianthus annus) spontaneously form parthenogenic haploids. Exploration of genetic, chemical and environmental factors demonstrated that a specific genotype enabled high parthenogenesis and that full‑spectrum high‑intensity light supplementation boosted parthenogenesis, yielding hundreds of haploid seeds per head.

Keywords: genome editing; hybridization; haploid induction; genome doubling

Presenter: Ashley Baldwin, Rakhee Dhorajiwala, Lama Alotaibi, Matthew Casey, Hans‑Wilhelm Nuetzmann, Tamara Lechon, Natasha Spadafora, Carsten Müller, Paul Devlin, Sarah Christofides, Hilary Rogers*

Affiliation: Cardiff University, UK; Imam Abdulrahman Bin Faisal University, Saudi Arabia; Royal Holloway University of London, UK; University of Exeter, UK; University of Ferrara, Italy

Email: rogershj@cardiff.ac.uk

Abstract: Fresh produce is important for its nutritional and ornamental value. However, fruits, fresh vegetables and cut flowers all have a very short shelf life. A combination of short time in the supply chain, and reduced temperature help to retain quality and safety of these products. However, the plant tissues from the different plant organs are still alive and able to respond to their postharvest environment. Understanding this response may help us to design better post‑harvest treatments and to breed plants with greater resilience. Plants produce thousands of different volatile organic compounds which are important as stress signals in leaves, communication with pollinators in flowers and with frugivores in fruit. They are also an easy‑to‑access readout of metabolic changes in response to post‑harvest stress. We have shown that the volatilome profile changes both in fruits and salads in response to post‑harvest storage. This change is species‑specific and modulated by storage temperature. Of current relevance in the face of climate change is the effect of pre‑harvest stresses on post‑harvest quality. We showed that in rocket salad pre‑harvest stresses affect both the volatilome and the transcriptome, with effects on physiology and metabolism. Post‑harvest storage in rocket salad changes the expression of stress‑related signalling modules and down‑regulates the expression of over 6000 genes. This might be linked to epigenetic factors. Using ChIP‑seq in strawberry we have shown that a repressive chromatin mark H3K27me3 is linked to changes in expression in 400 genes, including two transcription factors important for aroma development. In flowers, post‑harvest storage conditions need to ensure retention of shelf‑life even in complex flowers such as dahlias. We have used transcriptomics to explore the contribution of different pathways to gene regulation in flowers during senescence. Overall, omics approaches enable us to access a full picture of post‑harvest changes and how both pre‑ and post‑harvest treatments influence shelf‑life.

Keywords: postharvest; transcriptome; volatilome; epigenetics; chromatin

Presenter: Jian Lv*

Affiliation: State Key Laboratory of Crop Germplasm Innovation and Molecular Breeding, Syngenta Biotechnology (China) Co. Ltd., Beijing, China; Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China

Email: lvjian9646@aliyun.com

Abstract: Crop breeding is a fundamental agricultural practice that involves selecting plants with desirable traits and using them to produce the next generation of crops. This review highlights the advancements in Breeding 4.0, emphasizing new breeding technologies (NBT) that accelerate breeding, improve delivery efficiency, and reduce costs. To accelerate breeding, Doubled Haploid (DH) technology and genome editing have significantly shortened the development of inbred lines. Genomic selection leverages whole‑genome data to predict breeding values, optimizing the selection process. Speed breeding techniques, involving controlled environmental conditions, further expedite the breeding cycle. For improving delivery, innovative methods such as HI‑Edit™ and Virus‑Induced Gene Editing (VIGE) offer transgene‑free and efficient genome editing. Graft‑Based Genome Editing (GBGE) explores RNA transport mechanisms for non‑transgenic modifications. In cost reduction, advancements in male sterility systems, including genetic and cytoplasmic male sterility (CMS), streamline hybrid seed production. Techniques like environment‑sensitive genic female sterility (EGFS) enable cost‑effective hybrid seed generation. These technologies collectively enhance breeding precision, efficiency, and sustainability, offering significant potential for food security and agricultural development.

Keywords: crop breeding; DH technology; speed breeding; seed production

Presenter: Kexuan Tang*

Affiliation: Yazhouwan National Laboratory, Sanya, Hainan, China

Email: tangkexuan@yzwlab.cn

Abstract: Synthetic biology refers to the redesign and modification of natural biological systems by synthesizing new biological components, parts, and systems under the guidance of engineering principles, combining biotechnology to efficiently produce products needed by humans or even create new life forms. An important goal of plant synthetic biology is to enhance the production of valuable natural products through enabling technologies such as gene editing and metabolic engineering. Medicinal plants contain numerous natural products, which hold significant value in pharmaceuticals, agriculture, and industry. Humans rely heavily on medicinal plants, plant extracts, and their derivatives for health maintenance and disease treatment. For instance, tanshinones in Salvia miltiorrhiza have the efficacy to prevent and treat cardiovascular diseases, while artemisinin in Artemisia annua serves as the primary component of artemisinin‑based combination therapies for malaria. However, many crucial natural products are present in low concentrations in their source plants. Exploring effective synthetic biology strategies to enhance the production of these compounds in plants is crucial for reducing production costs and ensuring their sustainable, low‑cost supply. This talk takes artemisinin and tanshinone as case studies to explore the development of effective synthetic biology strategies for enhancing their content in source plants. These strategies include overexpressing biosynthetic pathway genes, downregulating competitive pathway genes, indirect regulation, transcriptional regulation, increasing glandular trichome density, and transport strategies. By employing these strategies individually or in combination, we have developed Artemisia annua with high artemisinin content and Salvia miltiorrhiza with high tanshinone content. These findings contribute to reducing the production costs of these important compounds, benefiting patients with malaria and cardiovascular diseases.

Keywords: artemisinin; metabolic engineering; plant synthetic biology; regulation; tanshinone

Presenter: Li WANG*

Affiliation: Agricultural Genomics Institute at Shenzhen (AGIS), Chinese Academy of Agricultural Sciences (CAAS), China

Email: wanglilab@caas.cn

Abstract: Evolution plays a magic role in driving plant biodiversity, which produces a profound chemical diversity when interacting with variable environments. Our lab focused on questions regarding DNA and chemical languages of medicinal plants. Specifically, we are fascinated with the following questions: (1) What is the origin and evolutionary path of medicinal plants? (2) How are bioactive compounds synthesized in plants? (3) Why do some plants produce one type (or high content) of secondary metabolites, while others not? Taking Apiaceae medicinal plants as study organisms, (1) we have revealed the homoploid hybrid speciation of Ligusticum chuanxiong and identified enzymes catalyzing the interconversion of phthalide compounds, one of which (butylphthalide; NBP) is the first‑line drug curing ischemic stroke; (2) we have dissected the complete biosynthetic pathway of furochromones in Saposhnikovia divaricate and traced the evolutionary history of two key enzymes involved in the pathway in Apiaceae, which explains the specifically high content of furochromones in S. divaricate.

Keywords: biosynthetic pathway; butylphthalide; comparative genomics; evolution; furochromone

Presenter: Zheyong Xue*

Affiliation: China National Rice Research Institute, Hangzhou, Zhejiang, China

Email: xuezheyong@caas.cn

Abstract: The heterologous biosynthesis of plant natural products faces several challenging issues, including pathway elucidation, optimization, and chassis selection, particularly for complex metabolites like steroidal saponins, whose biosynthetic pathways are lengthy and intricate. By integrating systematic phylogenetic trees and multi‑omics correlation analysis, an effective method for analyzing complex plant metabolic pathways in heterologous expression systems was established. This involves screening candidate genes one by one to elucidate the biosynthetic network from cycloartenol to cholesterol in Paris polyphylla. Based on this, we combined the transient expression of ten genes from the cholesterol synthesis pathway in P. polyphylla, achieving an efficient cholesterol biosynthesis method with a yield of 5.63 mg/g dry weight. Utilizing this strategy, we further clarified the biosynthetic pathway from cholesterol to diosgenin, constructing a diosgenin synthesis system in Nicotiana benthamiana with a yield of 2.12 mg/g dry weight. Finally, we identified glycosyltransferases from P. polyphylla that synthesize various polyphyllins and established an efficient method for synthesizing polyphyllin V.

Keywords: Paris polyphylla; Nicotiana benthamiana; cholesterol; diosgenin; biosynthetic pathway; steroidal saponins

Presenter: Hongxing Wang†, Jie Ren†, Shiyun Zhou, Yaoyuan Duan, Chenqiao Zhu, Chuanwu Chen, Ziyan Liu, Qingyou Zheng, Shu Xiang, Zongzhou Xie, Xia Wang, Lijun Chai, Junli Ye, Qiang Xu, Wenwu Guo, Xiuxin Deng*, Fei Zhang*

Affiliation: National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, HZAU, Wuhan, China

Email: xxdeng@mail.hzau.edu.cn; feizhang@mail.hzau.edu.cn

Abstract: Secretory structures in terrestrial plants serve as reservoirs for a variety of secondary metabolites. Among these, the secretory cavity of the Rutaceae family is notable for containing essential oils with a wide range of applications. However, the molecular basis underlying secretory cavity development is unknown. Here, we reveal a molecular framework for Citrus oil gland formation. Using genetic mapping and genome editing, we demonstrated that this process requires LATE MERISTEM IDENTITY1 (LMI1), a key regulator of leaf serration. A conserved GCC box element of the LMI1 promoter recruits DORNROSCHEN‑like (DRNL) for transcriptional activation. This DRNL–LMI1 cascade triggers MYC5 activation, facilitating the development of oil glands and the biosynthesis of essential oils.

Presenter: Ruimin Yu, Jin Y, Liu L, Zhang Y, Wu X, Zuo Y, Qi Y, Yang Z, Zhou J, Xu M, Nie J, Ding B, Birch P.R.J., Tian Zhendong*

Affiliation: National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, HZAU, Wuhan, China; Key Laboratory of Potato Biology and Biotechnology (HZAU), MARA, China; Potato Engineering & Technology Research Centre of Hubei Province (HZAU), China

Email: tianzhd@mail.hzau.edu.cn

Abstract: Potato late blight, caused by the oomycete Phytophthora infestans, is one of the most destructive plant diseases in the world, causing major losses in potato production. BABA application has been reported to enhance potato late blight resistance as well as in post‑harvest tubers, and the defense status stimulated by BABA can be passed on to its asexually reproduced offspring. In this study, we identified the potato BABA receptor StIBI1 and further explored how StIBI1 interacts with two NAC transcription factors (TFs), StVOZ1 and StVOZ2 to regulate late blight resistance. StVOZ1 is a negative regulator, on the contrary, StVOZ2 is a positive regulator for P. infestans. We found that overexpression of StIBI1 in potato enhances late blight resistance even without BABA pretreatment; StIBI1 interacts with StVOZ1 and StVOZ2 in the cytoplasm and affects the stability and nuclear translocation of StVOZ1/2 proteins to activate BABA‑IR in a more fine‑grained regulatory manner, which further regulates the expression of downstream disease resistance‑related genes in different pathways to enhance late blight resistance. Our findings enrich the information on how BABA primes potato late blight resistance, providing new strategies for protecting potato against P. infestans.

Presenter: Qingguo Zeng, Minghua Wei, Shuai Li, Haiyan Wang, Changjuan Mo, Li Yang, Xinzheng Li, Zhilong Bie*, Qiusheng Kong*

Affiliation: National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, HZAU, Wuhan, China

Email: biezl@mail.hzau.edu.cn; qskong@mail.hzau.edu.cn

Abstract: Pumpkin (Cucurbita maxima) is a globally cultivated vegetable crop with great economic significance. A high‑quality complete genome sequence is crucial for genetic and genomic research. To improve the draft genome of C. maxima, the data of HiFi, ultra‑long ONT, and Hi‑C were used to de novo assemble a telomere‑to‑telomere and gap‑free genome for C. maxima in this study. The complete genome was 345.1 Mb in size with contig N50 of 16.4 Mb and 28,329 protein‑coding genes, which introduced 133.6 Mb new sequences compared with the previously published pumpkin draft genome. Six types of monomers with the lengths of 169 bp, 253 bp, 315 bp, 324 bp, 327 bp, and 654 bp were identified in the centromeres, which contributed to five unique types of chromosome‑specific centromeres in the pumpkin genome. Collectively, these results provide not only a valuable high‑quality genome resource but also a comprehensive insight into the genome architecture of C. maxima.

Presenter: Ziqing Huang*, Pang Ruonan, Kuang Hanhui, Zeng Yunliu

Affiliation: National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, HZAU, Wuhan, China

Email: 19921629717@189.cn

Abstract: Wax powder, as its own physiological structure formed during the long‑term evolution of plants to adapt to the external natural environment, covers the surface of plant leaves. It can reduce ultraviolet radiation, reduce non‑stomatal water loss and prevent plants from losing too much water due to transpiration. However, the molecular mechanism of how to synthesize/delete wax powder in lettuce has not yet been reported, and the relevant mutant library has not yet been established. We use the forward genetics method (BSA + RNA‑seq) to provide the molecular basis for improving the regulation principle of lettuce breeding.